head to head
Grand Theft Auto V asks more than Metro: Last Light, and the gap is reads.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Practiced Mastery
Refined sequel deepening Metro's stealth and moral undercurrents.
Grand Theft Auto V leans Execution (Practiced Mastery); Metro: Last Light leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Metro: Last Light
tighter gunplay than 2033, still deliberate
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Metro: Last Light
scripted enemy encounters
Metro: Last Light leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Metro: Last Light
hidden morality system opaque first time
Metro: Last Light leans a little harder on optimization, though the gap is small.
Grand Theft Auto V
Heists, money loops, builds learnable.
Metro: Last Light
stealth routes and resource management
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.